Harriet

Same amount works, and a lot of bakers use about a quarter less going from active dry to an instant type. Either way you can skip the proof. Fresh cake yeast is the odd one out: roughly a third of the fresh weight.

Bread machine yeast is instant yeast. Some brands put in a small amount of something like ascorbic acid to help a machine's rise, but for hand baking it behaves the same way: mix it straight into the dry ingredients, no proofing needed, works in pizza dough and rolls and ordinary bread.

So use the same amount your recipe asks for and skip the proofing step entirely. Mix it into the flour with the salt rather than letting the two sit in a concentrated pile together.

One real difference in behaviour rather than ingredients: instant types work a bit faster than active dry. So if the recipe was written for active dry, start checking your dough earlier than it tells you to rather than trusting the clock.

If you want better pizza out of the same jar, use a little less yeast and let the dough rise in the fridge for one to three days. Cold fermentation does more for flavour and crust than the choice of yeast ever will.